14 Questions
Which of the following is NOT an advantage of solid state fermentation (SSF) over submerged fermentation?
Sterilization of the medium is not critical
What is a key consideration in the design and control strategies of a reactor for solid state cultivation?
Variety of materials used as growth media
Which type of SSF bioreactor is based on aeration or the mixed system employed?
Stirred bioreactor
What characteristic of growth media used in SSF bioreactors poses problems for the heat transfer system?
Low water activity
In SSF, why is the sterilization of the medium often unnecessary?
Low water activity used in SSF
Why are bioreactors mostly applied in laboratory scale rather than pilot and industrial scale?
Hyphae can be damaged by mechanical agitation, solid medium compaction, difficulties with inoculation, control, and sterilization of large volumes of medium, maintenance and procedures for large reactors
What problems are caused by solid medium compaction during the process?
Reduced aeration, reduced heat transfer, difficulties with inoculation, control, and sterilization of large volumes of medium
What challenges are associated with the maintenance and procedures for filling, emptying, and cleaning of large reactors?
Difficulties with inoculation, control, and sterilization of large volumes of medium, lack of uniformity in large volumes of biomass, solid medium compaction, mechanical agitation
Why is the maintenance of uniformity difficult for large volumes of biomass?
Hyphae can be damaged by mechanical agitation, solid medium compaction, difficulties with inoculation, control, and sterilization of large volumes of medium
What is a significant challenge associated with tray reactors for solid state fermentation?
Difficulty in maintaining uniform oxygen concentration throughout the substrate layers
Why does the diffusion rate of O2 transport properties depend on the tray in tray reactors?
The substrate layer shrinks over time, altering the porosity and effective diffusivity
What problem arises as a result of the shrinkage of the substrate layer in tray reactors?
Altered porosity leading to non-uniform O2 concentration
Why does the oxygen concentration become non-uniform in tray reactors over time?
Shrinkage of the substrate layer alters porosity and effective diffusivity
What is a major limitation of tray reactors in solid state fermentation?
Inability to maintain uniform oxygen concentration as the substrate shrinks
Study Notes
Solid State Fermentation (SSF) Advantages and Challenges
- Lower energy requirements and waste generation are advantages of SSF over submerged fermentation, but not higher capital investment.
Bioreactor Design and Control Strategies
- Key consideration in reactor design and control strategies is the maintenance of uniform temperature and moisture levels.
Bioreactor Types
- The static packed bed bioreactor is based on aeration or mixed systems.
Growth Media Characteristics
- High water-holding capacity of growth media in SSF bioreactors poses problems for heat transfer systems.
Sterilization of Medium
- Sterilization of the medium is often unnecessary in SSF because the high temperature and low water content inhibit microbial growth.
Bioreactor Scalability
- Bioreactors are mostly applied in laboratory scale due to challenges in scaling up, such as maintaining uniformity and controlling temperature.
Solid Medium Compaction
- Solid medium compaction during the process leads to reduced growth rates, decreased oxygen diffusion, and increased heat generation.
Large Reactor Maintenance
- Challenges associated with large reactors include maintenance and procedures for filling, emptying, and cleaning, which can be time-consuming and costly.
Uniformity Maintenance
- Maintaining uniformity is difficult for large volumes of biomass due to variations in temperature, moisture, and oxygen levels.
Tray Reactors
- A significant challenge associated with tray reactors is the difficulty in maintaining uniform oxygen levels and temperature.
- The diffusion rate of O2 transport properties depends on the tray in tray reactors, which can affect growth rates.
- The shrinkage of the substrate layer in tray reactors can lead to reduced growth rates and increased heat generation.
- Oxygen concentration becomes non-uniform in tray reactors over time, affecting growth rates and product formation.
- A major limitation of tray reactors is the difficulty in scaling up while maintaining uniform conditions.
Learn about the biotechnological advantages of solid state fermentation over submerged fermentation, including higher productivity, concentration of end products, product stability, and more. Explore the unique characteristics and benefits of SSF in biotechnology.
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